AMD Ryzen 7 PRO 7840HS vs AMD Ryzen 5 4500U

AMD Ryzen 7 PRO 7840HS

The AMD Ryzen 7 PRO 7840HS is a fast high-end laptop processor of the Phoenix series. It offers 8 cores (octa core) based on the Zen 4 architecture that supports hyperthreading (16 threads). The cores clock from 3.8 (base) up to 5.1 GHz (single core boost). The processor includes 8 MB L2 cache and 16 MB L3 cache.

Compared to the consumer Ryzen 7 7840HS, the PRO models offer additional security, manageability, and reliability features designed for professional users and workstation environments.

The performance of the R7 PRO 7840HS is only slightly below the fastest model, the R9 PRO 7940HS, as the clock speed difference is only minimal (e.g. -100 MHz / 2% slower single core boost). Therefore, the CPU should also perform slightly higher than the old top model Ryzen 9 6980HX (8 Zen 3 cores with up to 4.9 GHz) at 54W TDP and Ryzen 9 6980HS at 35W TDP. Compared to the higher end Dragon Range series, the 7840HS should be similar to the Ryzen 7 7745HX (also 8 Zen 4 cores, max 5.1 GHz, 55W TDP, 32 MB L3).

The chip integrates a modern and fast RDNA 3 graphics adapter (iGPU) called Radeon 780M with 12 CUs and up to 2.7 GHz clock speed. Furthermore, the Phoenix series include a video engine with AV1 de- and encoding, a new Xilinx FPGA based XDNA AI accelerator (Ryzen AI) that should be faster than the AI engine in the Apple M2 SOC and a dual-channel DDR5-5600 / LPDDR5x-7500 memory controller (with ECC support). The connectivity features includes 2 possible USB 4 (40 Gbps) ports and 20 PCIe 4.0 lanes for a GPU and SSDs.

The Phoenix series uses a single monolithic design (unlike the chiplet design of the 7045HX series) and is manufactured on the modern 4nm process at TSMC. The TDP can be configured between 35 and 45 Watt.

AMD Ryzen 5 4500U

The AMD Ryzen 5 4500U is an upper mid-range, hexa-core processor of the Renoir product family. The APU was unveiled in H1 2020; it is designed for use in thinner, lighter laptops. Its six Zen 2 CPU cores run at 2.3 GHz (base clock speed) to 4.0 GHz (highest Boost frequency possible). Ryzen 5 4500U features the Vega 6 iGPU.

The sole advantage of Ryzen 5 4600U over Ryzen 5 4500U is the thread-doubling SMT technology support. The former has SMT while the latter does not.

Architecture

Zen 2 is a resounding success, delivering massive improvements over outgoing Zen Plus-based processors. Ryzen 5 4500U is manufactured on the cutting-edge 7 nm TSMC process; it is compatible with dual-channel DDR4-3200 or quad-channel LPDDR4-4266 memory. This processor has 8 MB of Level 3 cache.

While the APU uses Zen 2 cores just like the desktop-grade Ryzen 3000-series processors do, Ryzen 7 3800XT included, it does does not have PCI-Express 4.0 support. It does feature several PCI-Express 3.0 lanes for connecting discrete graphics cards, SSDs and other devices. Four PCI-Express 3.0 lanes allow for read/write rates of up to 3.9 GB/s provided a suitably fast NVMe SSD is used.

Ryzen 5 4500U gets soldered permanently on to the motherboard (FP6 socket interface) and is anything but user-replaceable.

Performance

The average Ryzen 5 4500U in our database nearly matches the Core i5-11300H, the Core i5-11320H and also the AMD Ryzen 3 5300U as far as multi-thread benchmark scores are concerned - thus delivering an undeniably impressive performance jump over the outgoing Ryzen 5 3500U.

Thanks to its decent cooling solution and a long-term power limit of 38 W, the Xiaomi RedmiBook 16 R5 is among the fastest systems powered by the R5 4500U that we know of. It can be about 20% faster in CPU-bound workloads than the slowest system built around the same chip in our database, as of August 2023.

Graphics

Just like its name suggests, the Radeon RX Vega 6 graphics adapter has 6 Compute Units (6 x 64 = 384 unified shaders). In the case of Ryzen 5 4500U, this graphics adapter runs at up to 1,500 MHz. The iGPU definitely supports UHD 2160p monitors at 60 Hz; it will have no trouble HW-decoding HEVC, AVC, VP9, MPEG-2 and other widespread video codecs. AV1 is not supported though; such a video will have to be software-decoded for much lower energy efficiency.

Vega 6 will let you play many titles of 2020 and 2021 as long as you stick to low settings and low resolutions. F1 2021 (720p, Low) runs at 32 fps; Outriders (720p, Low) runs at 27 fps, to give you an example or two. As the iGPU has no VRAM of its own, it is paramount that fast system RAM is used.

Power consumption

This Ryzen chip is very energy efficient, as of mid 2022, thanks to the cutting-edge 7 nm TSMC manufacturing process and the mature Zen 2 architecture.

The Ryzen 5 4500U has a default TDP (also known as the long-term Power Limit) of 15 W that can be changed to anything between 10 W and 25 W by laptop makers if required, a right they use more often than not. Clock speeds and performance will change accordingly as a result. By going for the lowest value, it will be possible to use the APU as the heart of a passively cooled tablet, laptop, mini-PC.